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https://issues.apache.org/jira/browse/DRILL-1887?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14253542#comment-14253542
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Aman Sinha commented on DRILL-1887:
-----------------------------------
If nulls are not equal and only one side is null the comparator was working
correctly so I did not change that logic; however your suggestion to bypass it
seems reasonable...I will make that change.
> Wrong result for hash join on null valued columns
> -------------------------------------------------
>
> Key: DRILL-1887
> URL: https://issues.apache.org/jira/browse/DRILL-1887
> Project: Apache Drill
> Issue Type: Bug
> Reporter: Rahul Challapalli
> Assignee: Aman Sinha
> Attachments:
> 0001-DRILL-1887-Add-code-gen-for-explicitly-comparing-nul.patch
>
>
> git.commit.id.abbrev=9dfa4a1
> Dataset1:
> {code}
> {
> "col1":1,
> "col2":"abc"
> }
> {
> "col1":2,
> "col2":null
> }
> {code}
> Dataset 2:
> {code}
> {
> "col1":1,
> "col2":null
> }
> {
> "col1":2,
> "col2":null
> }
> {
> "col1":2,
> "col2":"abc"
> }
> {code}
> Query :
> {code}
> select * from `a.json` a join `b.json` b on a.col2=b.col2;
> +------------+------------+------------+------------+
> | col1 | col2 | col10 | col20 |
> +------------+------------+------------+------------+
> | 1 | abc | 2 | abc |
> | 2 | null | 1 | null |
> | 2 | null | 2 | null |
> +------------+------------+------------+------------+
> {code}
> Most database engines treat 2 NULL values as not being equal. This makes it
> hard to compare DRILL's results against any Standard SQL engine. However I am
> not sure whether drill is intentionally designed to behave this way.
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